What @roelschroeven says. CPU Time is a metric of how much 'real time' was spent on the process, so a single thread running 100% time [on a single core with no

What @roelschroeven says. CPU Time is a metric of how much 'real time' was spent on the process, so a single thread running 100% time [on a single core with no HT] would give you a full 'real time' second. System idle 'consumes' all the idle CPU time so if the system is doing nothing it's get a second of CPU Time per execution thread. And there are multiple execution threads on almost anything later than 2005. On my T440 with i3-4010U (2 cores, 4 threads) the System Idle consumes ~3 seconds of CPU Time per second, because there are ton of shit running in the background so the system is never 100% idle.